1. Field of the Disclosure
The disclosure relates generally to drilling of wellbores and particularly to a drilling assembly that utilizes an electro-mechanical actuation device for tilting a disintegrating device for drilling deviated wellbores.
2. Background Art
Wells or wellbores are formed for the production of hydrocarbons (oil and gas) from subsurface formation zones where such hydrocarbons are trapped. To drill a deviated wellbore, a drill string carrying a drilling assembly (also referred to as a bottomhole assembly or “BHA”) at its bottom is conveyed in the wellbore. A drill bit attached to the bottom of the drilling assembly is rotated by rotating the drill string and/or by a drilling motor in the drill string to disintegrate formation rock to drill the wellbore. A substantial portion of the currently formed wellbores are deviated and/or horizontal wellbore. For the purpose of this disclosure a “deviate wellbore” mean any wellbore or section thereof that is not vertical. A steering device in the drilling assembly is typically utilized to tilt a lower section or portion of the drilling assembly to form deviated wellbores. The steering device tilts the lower portion or section of the drilling assembly by a selected amount and along a selected direction to form the deviated portion of the wellbore. Various types of steering devices disposed in the drilling assembly that tilt a section of the drilling assembly itself have been proposed and used for drilling deviated wellbores. More recently, a hydraulic steering device in the drilling assembly that tilts the drill bit about a joint in the drill bit is disclosed in U.S. Pat. No. 9,145,736, assigned to the assignee of this application. The drilling assembly also includes a variety of sensors and tools that provide information relating to the earth formation, drilling parameters and drilling assembly orientation. A control unit or controller is often utilized to control the tilt of the drilling assembly or the drill bit in response to one or more parameters obtained from such sensors.
The disclosure herein provides a drilling assembly in which an electro-mechanical actuation device tilts the drill bit about a joint in the drill bit to drill deviated wellbores.